Chemical mechanical polishing (CMP) is generally known in the art. For example U.S. Pat. No. 5,177,908 to Tuttle issued in 1993 describes a finishing element for semiconductor wafers, having a face shaped to provide a constant, or nearly constant, surface contact rate to a workpiece such as a semiconductor wafer in order to effect improved planarity of the workpiece. U.S. Pat. No. 5,234,867 to Schultz et. al. issued in 1993 describes an apparatus for planarizing semiconductor wafers which in a preferred form includes a rotatable platen for polishing a surface of the workpiece and a motor for rotating the platen and a non-circular pad is mounted atop the platen to engage and polish the surface of the semiconductor wafer. Fixed abrasive finishing elements are also known for polishing semiconductor layers. An example is WO 98/18159 PCT application by Minnesota Mining and Manufacturing.
Semiconductor wafer fabrication generally requires the formation of layers of material having particularly small thickness. A typical conductor layer, such as a metal layer, is generally 2,000 to 6,000 angstroms thick and a typical insulating layer, for example a an oxide layer, is generally 3,000 to 5,000 angstroms thick. The actual thickness is at least partially dependent on the function of the layer along with the function and design of the semiconductor wafer. A gate oxide layer can be less than 100 angstroms while a field oxide is in the thousands of angstroms in thickness. In higher density and higher value semiconductor wafers the layers can be below 500 angstroms in thickness. Generally during semiconductor fabrication, layers thicker than necessary are formed and then thinned down to the required tolerances with techniques needed such as Chemical Mechanical Polishing. Because of the strict tolerances, extreme care is given to attaining the required thinned down tolerances. As such, it is important to accurately determine just when enough of the layer has been removed to reach the required tolerances, this is the end point for the thinning or polishing operation. One method to remove selected amounts of material is to remove the semiconductor wafer periodically from polishing for measurements such as thickness layer measurements. Although this can be done it is time consuming and adds extra expense to the operation. Further the expensive wafers can be damaged during transfer to or from the measurement process further decreasing process yields and increasing costs.
Confidential applicant evaluations also suggest that lubricants supplied to the interface between the workpiece surface being finished and the polishing pad polishing surface can improve finishing. Addition of lubricants to the interface between the workpiece surface being finished and the polishing pad polishing surface can improve finishing but also changes the friction at this interface. In situ process control where lubricants are added or changed during the finishing process can change finishing performance. A method to detect in process changes due to lubricant additions and/or changes is needed in the industry. A method which can also help improve the cost of manufacture of the semiconductor wafers during a finishing cycle time having real time friction changes would be generally desirable.
As discussed above, there is a need for in situ detector for CMP and other finishing techniques which will function with or without the addition lubrication to the finishing interface. There is a need for an in situ detector and control of CMP and other finishing control parameters which account for and adjust for the addition and/or control of lubrication at the finishing interface. There is a need for an in situ detector and control of CMP and other finishing control parameters which detect the endpoint and/or/stop the CMP and/or other finishing processes. There is a need to use cost of manufacture parameters for real time process control when using operative friction sensors. There is a need to use real time process control and current cost of manufacture with active lubrication of the interface to improve the finishing costs.
It is an advantage of this invention to develop an in situ friction sensor subsystem and finishing sensor subsystem for CMP and other finishing techniques and methods which function with or without the addition lubrication to the finishing interface. It is an advantage of this invention to develop an in situ friction sensor subsystem and finishing sensor subsystem for control of CMP and other finishing control parameters which account for and adjust for the addition and/or control of lubrication at the finishing interface. It is an advantage of this invention to develop an in situ friction sensor subsystem and finishing sensor subsystem CMP and other finishing control parameters which detect the endpoint and stop the CMP and/or other finishing processes. It is an advantage of this invention to use cost of manufacture parameters for real time process control when using operative friction sensors. It is an advantage of this invention to develop to use real time process control and current cost of manufacture with active lubrication of the interface to improve the finishing costs. It is an advantage of this invention to develop a method which can also help improve the cost of manufacture of the semiconductor wafers during a finishing cycle time having real time friction changes.
These and other advantages of the invention in preferred embodiments will become readily apparent to those of ordinary skill in the art after reading the following disclosure of the invention.
A preferred embodiment of this invention is directed to a finishing apparatus comprising a workpiece carrier for holding workpiece surface to finished; a finishing element finishing surface positioned proximate the workpiece surface to be finished; a mechanism for applying an operative finishing motion to the operative finishing interface comprising workpiece surface to be finished and finishing element finishing surface; and a friction control subsystem having at least one friction sensor probe having a friction sensor surface proximate to the finishing element finishing surface and free of contact with the workpiece surface and the friction sensor subsystem being capable of in situ control of a finishing control parameter.
A preferred embodiment of this invention is directed to a finishing apparatus comprising a workpiece carrier for holding workpiece surface to finished; a finishing element finishing surface positioned proximate the workpiece surface to be finished; a mechanism for applying an operative finishing motion to the operative finishing interface comprising workpiece surface to be finished and finishing element finishing surface; and a friction control subsystem having at least one friction sensor probe having a friction sensor surface proximate to the finishing element finishing surface and free of contact with the workpiece surface, the friction sensor probe capable of measuring a change in tangential force of friction and the friction sensor subsystem being capable of in situ control of a finishing control parameter responsive to a signal from the friction sensor probe.
A preferred embodiment of this invention is directed to a finishing apparatus comprising a semiconductor wafer carrier for holding semiconductor wafer surface to be finished; a finishing element finishing surface positioned proximate the semiconductor wafer surface to be finished; a mechanism for applying an operative finishing motion to the operative finishing interface comprising the semiconductor wafer surface to be finished and finishing element finishing surface; and a friction control subsystem having at least one friction sensor probe having a friction sensor surface proximate to the finishing element finishing surface and free of contact with the semiconductor wafer surface and the friction sensor subsystem being capable of in situ control of a finishing control parameter.
A preferred embodiment of this invention is directed to a finishing apparatus comprising a semiconductor wafer carrier for holding the semiconductor wafer surface to be finished; a finishing element finishing surface positioned proximate the semiconductor wafer surface to be finished; a mechanism for applying an operative finishing motion to the operative finishing interface comprising the semiconductor wafer surface to be finished and finishing element finishing surface; and friction control subsystem having at least one friction sensor probe having a friction sensor surface proximate to the finishing element finishing surface and free of contact with the semiconductor wafer surface, the friction sensor probe capable of measuring a change in tangential force of friction and the friction sensor subsystem being capable of in situ control of a finishing control parameter responsive to a signal from the friction sensor probe.
A preferred embodiment of this invention is directed to a method of finishing of a semiconductor wafer surface comprising a step 1) of providing a finishing element finishing surface; a step 2) of positioning the semiconductor wafer surface being finished proximate to the finishing element finishing surface; a step 3) of providing an organic lubricant to the interface formed between the semiconductor wafer surface and the finishing element finishing surface; a step 4) of providing at least one operative friction sensor capable of gaining information about the finishing; a step 5) of applying an operative finishing motion between the semiconductor wafer surface being finished and the finishing element finishing surface forming an operative finishing interface having a friction; a step 6) of sensing the friction with the operative friction sensor and sending the information about the friction to a processor having access to current cost of manufacture parameters; a step 7) of evaluating finishing control parameters for improved adjustment using at least in part a minimum of two cost of manufacture parameters; and a step 8) of controlling at least two process control parameters to improve the cost of manufacture of the semiconductor wafer.
A preferred embodiment of this invention is directed to a method of finishing of a semiconductor wafer surface having a finishing cycle time comprising a step 1) of providing a finishing element finishing surface; a step 2) of positioning the semiconductor wafer surface being finished proximate to the finishing element finishing surface; a step 3) of providing an organic lubricant to the interface formed between the semiconductor wafer surface and the finishing element finishing surface; a step 4) of providing at least two operative friction sensors capable of gaining information about the finishing; a step 5) of applying an operative finishing motion between the semiconductor wafer surface being finished and the finishing element finishing surface forming an operative finishing interface with at least one friction; a step 6) of sensing friction with the at least two operative friction sensors and sending the information about the finishing to a processor having access to useful cost of manufacture parameters; a step 7) of evaluating finishing control parameters for improved adjustment using at least in part a minimum of three useful cost of manufacture parameters; and a step 8) of controlling and adjusting at least 4 times a minimum of two process control parameters to improve the cost of manufacture of the semiconductor wafer during the finishing cycle time.
A preferred embodiment of this invention is directed to a method of finishing of a semiconductor wafer surface having a finishing cycle time comprising a step 1) of providing an abrasive finishing surface; a step 2) of positioning the semiconductor wafer surface being finished proximate to the finishing element finishing surface; a step 3) of providing an organic lubricant and a finishing composition to an interface formed between the finishing element finishing surface and the semiconductor wafer surface; a step 4) of providing at least one operative friction sensor capable of gaining information about the finishing; a step 5) of applying an operative finishing motion between the semiconductor wafer surface being finished and the finishing element finishing surface forming an operative finishing interface; a step 6) of sensing the progress of the finishing of the semiconductor wafer surface with the operative sensor and sending the information about the finishing to a processor having access to current cost of manufacture parameters; a step 7) of evaluating finishing control parameters for improved adjustment using at least in part a minimum of three current cost of manufacture parameters; and a step 8) of controlling two process control parameters at least 4 times during the finishing cycle time to improve the cost of manufacture of the semiconductor wafer.
A preferred embodiment of this invention is directed to a method of finishing of a semiconductor wafer surface comprising a step 1) of providing a finishing element finishing surface; a step 2) of positioning the semiconductor wafer surface proximate to the finishing element finishing surface; a step 3) of providing an organic lubricant and a finishing composition to an interface formed between the finishing element finishing surface and the semiconductor wafer surface; a step 4) of providing at least one operative friction sensor capable of gaining information about the finishing; a step 5) of applying an operative finishing motion between the semiconductor wafer surface being finished and the finishing element finishing surface forming an operative finishing interface; a step 6) of sensing the progress of the finishing of the semiconductor wafer surface with the operative sensor and sending the information about the finishing to a processor having access to useful cost of manufacture parameters; a step 7) of evaluating finishing control parameters for improved adjustment using at least in part at least two useful cost of manufacture parameters; and a step 8) of controlling at least two process control parameters to improve the cost of manufacture of the semiconductor wafer.
A preferred embodiment of this invention is directed to a method of finishing having a finishing cycle time comprising a step 1) of providing a semiconductor wafer having a tracking code; a step 2) of providing a finishing element finishing surface; a step 3) of positioning the semiconductor wafer surface being finished proximate to the finishing element finishing surface; a step 4) of providing a lubricant to the interface formed between the semiconductor wafer surface and the finishing element finishing surface; a step 5) of providing at least one operative friction sensor capable of gaining information about the finishing; a step 6) of applying an operative finishing motion between the semiconductor wafer surface being finished and the finishing element finishing surface forming an operative finishing interface having a friction; a step 7) of sensing the friction with the operative friction sensor and sending the information about the friction to a processor having access to current cost of manufacture parameters; a step 8) of evaluating finishing control parameters for improved adjustment using at least in part a minimum of a plurality of the current cost of manufacture parameters; and a step 9) of controlling at least two process control parameters to improve the cost of manufacture of the semiconductor wafer.
A preferred embodiment of this invention is directed to a method of finishing comprising a step 1) of providing a semiconductor wafer having a tracking code; a step 2) providing an abrasive finishing surface; a step 3) of positioning the semiconductor wafer surface being finished proximate to the abrasive finishing surface; a step 4) of providing at least one operative friction sensor capable of gaining information about the finishing; a step 5) of applying an operative finishing motion between the semiconductor wafer surface being finished and the abrasive finishing surface forming an operative finishing interface having a friction; a step 6) of sensing the friction with the operative friction sensor and sending the information about the friction to a processor having access to current cost of manufacture parameters; a step 7) of evaluating using a mathematical formula to calculate in situ at least two improved process control parameter values based at least in part upon at least two cost of manufacture parameters selected from the group consisting of parametric yield, equipment yield, defect density, and finishing rate; and a step 8) of controlling at least two process control parameters to improve the cost of manufacture of the semiconductor wafer.
A preferred embodiment of this invention is directed a method of finishing of a workpiece surface being finished comprising the step of providing a finishing element finishing surface; the step of positioning the workpiece surface being finished proximate to the finishing surface; the step of providing at least one friction sensor probe having a friction sensor surface proximate to the finishing element finishing surface and free of contact with the workpiece surface; the step of applying an operative finishing motion to an operative finishing interface comprising the interface between the finishing element finishing surface and the workpiece surface being finished; the step of applying an operative friction sensor motion between the friction sensor surface and the finishing element finishing surface and wherein the operative friction sensor motion comprises applying a movement to friction sensor surface; the step of sensing a tangential friction force between the friction sensor surface and the finishing element finishing surface with a friction sensor subsystem; and the step of controlling in situ a finishing control parameter with the friction sensor subsystem.
A preferred embodiment of this invention is directed a method of finishing of a workpiece surface being finished comprising a step a) providing a finishing element finishing surface; a step b) positioning the workpiece surface being finished proximate to the finishing surface; a step c) providing at least one friction sensor probe having a friction sensor surface proximate to the finishing element finishing surface and free of contact with the workpiece surface; a step d) applying an operative finishing motion between the workpiece surface being finished and the finishing surface forming an operative finishing interface; a step e) applying an operative friction sensor motion between the friction sensor surface and the finishing element finishing surface; a step f) sensing the friction between the friction sensor surface and the finishing element finishing surface with a friction sensor subsystem; and a step g) controlling in situ a finishing control parameter with the friction sensor subsystem.
Another preferred embodiment of this invention is directed to a method of finishing of a workpiece surface being finished comprising a step a) providing a finishing element finishing surface; a step b) positioning the workpiece surface being finished proximate to the finishing surface; a step c) providing at least one friction sensor probe having a friction sensor surface proximate to the finishing element finishing surface and free of contact with the workpiece surface; a step d) providing a finishing element conditioner operatively connected for controlling through a finishing sensor subsystem during the finishing cycle; a step e) applying an operative finishing motion between the workpiece surface being finished and the finishing element finishing surface forming an operative finishing interface; a step f) applying an operative friction sensor motion between the friction sensor surface and the finishing element finishing surface; a step g) sensing the friction information between the friction sensor surface and the finishing element finishing surface with a friction sensor subsystem and transferring the sensed friction information to the finishing sensor subsystem; and a step h) controlling in situ at least one finishing element conditioning control parameter by using the friction information sensed between the friction sensor surface and the finishing element finishing surface with the finishing sensor subsystem.
Other preferred embodiments are discussed herein.